The present invention relates to a piezoelectric device for use with an electromechanical converting device or a mechanoelectric converting device.
Some well-known piezoelectric devices involve the use of ceramic materials such as PZT (a solid solution of lead titanate (PbTiO3) and lead zirconate (PbZrO3)) and polymeric materials such as PVDF (polyvinylidene fluoride). Those piezoelectric devices are widely utilized for electromechanical converting devices such as a sound emitting body for emitting sounds ranging from an audible region to an ultrasonic region, an actuator and a motor as well as for mechanoelectric converting devices such as a pressure sensor and the like.
In the case of a piezoelectric device using the ceramic materials, calcination has to be effected at high temperatures of 1000.degree..about.1500.degree. C., with the result that it is difficult to obtain dimensional accuracy. The ceramic materials tend to be broken due to their fragility, and are thereby thinned with difficulty.
In the case of the piezoelectric device employing the polymeric materials, the polymeric material formed in a film-like shape is mechanically stretched, as a result of which it is difficult to obtain the dimensional accuracy and make it thin.
As described above, the conventional piezoelectric devices are formed in arbitrary configurations with difficulty because of a variety of constraints.
The prior art piezoelectric devices require a poling process (DC high electric field is applied at a Curie temperature or above, and a cooling process continues till the temperature comes to the Curie temperature or under, thus aligning the directions of electric dipoles) in order to develop the piezoelectric property. Therefore, the manufacturing processes become complicated.
Accordingly, it is a primary object of the present invention to obviate the foregoing problems inherent in the prior art devices, and to provide an absolutely novel piezoelectric device and converting devices which utilize this piezoelectric device.